Never used it to clean filters but I have used it to regenerate gfo but that got old fast
Lye, the the strongest alkaloid we know it turns soft pretzels bronze it also decomposes matter quickly so I was thinking that you could soak use cartridges or in my case I make my own pads for my aquarium that consists of probably a lot of food not eaten and biological matter and then maybe after a thorough rinsing the pads would be good as new like I said I'm not suggesting or telling I'm just asking someone who's smarter than me.